JPS61142443A - Method and apparatus for detecting nitrous acid ion - Google Patents

Abstract

PURPOSE:To enable the detection and determination of NO<->2 in a liquid to be inspected accurately in a short time, by bringing a liquid being inspected in contact with a powder or particulate carrier layer supporting naphtyl ethylenediamine and sulfanylamide to to measure the possible coloring and the degree of coloring of the carrier layer. CONSTITUTION:A solution in which 5g of sulfanylamide and 5g of naphtyl ethylenediamine chlorate are dissolved into 100ml of water is mixed with 50g of a carrier such as active alumina and after the mixture is filtered, it is dried by evaporating water to support both reagents on the surface of carrier particles. The carrier 2 is placed into a glass tube 1 having a cotton 3 packed into the lower open end thereof to obtain an NO<->2 detector having the cotton 3 packed onto the carrier. The lower end of the tube 1 is immersed into a sample liquid to measured possible coloring (red) due to the NO<->2 ion in the water sucked up by a capillary phenomenon and the length of the colored layer 4. Thus, the concentration of an object in the sample in found from the relationship between the concentration and the length of the colored layer previously obtained with respect to the known concentration sample thereby enabling the measuring of NO<->2 handily as well as accurately.

Description

Detailed Description of the Invention: Industrial Field of Application This invention relates to nitrite added to circulating water and heat medium and to nitrite ions in water for rust prevention of cooling water piping materials and heat exchange equipment. The present invention relates to a method and device for easily detecting the concentration of a dissociated rust inhibitor.

BACKGROUND OF THE INVENTION It is known that nitrite dissociates into nitrite ions in water, reacts chemically with metal regions, and forms a passive film on the metal surface. Therefore, it is often used as a rust preventive agent for iron-based materials, as well as aluminum and lead. However, the rust prevention effect decreases rapidly due to damage to the coating or leakage of circulating water to the outside of the system, and pipes and equipment may become severely corroded in a short period of time. Therefore, it is necessary to periodically control the concentration of the rust preventive agent in the circulating water.

Conventionally, the method for measuring the nitrite ion concentration in water is to add sulfanilic acid to a sample, diazotize it with the nitrite ions in the sample7, and then add naphthylamine to produce a red azo compound, and measure the absorbance at a wavelength of around 520 nm. This is a method of quantitative determination using a calibration curve obtained from a sample of known concentration ((IISKO1o2), (AS
TMD1254)).

The reaction formula is shown below.

(Sulfanilic acid) (Diazo compound) This method requires complicated operations such as preparation of reagents, use of a colorimeter, skill level, and long time for quantitative determination. Therefore, it is inappropriate as a management analysis method in the field.

P′l! ! 4. In order to solve the above-mentioned problems, the present invention has been developed by filling a thin tube with a carrier insoluble in circulating water, a heating medium, etc., which carries a reaction reagent, and then absorbing nitrous acid in water that is sucked up by capillary action. The method is characterized in that ions are reacted or adsorbed with a reaction reagent or a carrier to produce a red color, and the concentration of nitrite ions in water can be easily measured based on the degree of coloration and the length of the colored layer.

Function The present invention selectively separates, reacts or adsorbs nitrite ions in water. That is, according to the method of the present invention, water in the sample is drawn up into the filler layer within the capillary tube by capillary action. Here, the nitrite ion reacts with the powder or granular material carrying the reaction reagent to produce a red diazo compound.

At the same time, it also has an adsorption effect, forming a red colored layer with a certain length in proportion to the amount of nitrite ions. Generally, among these powdery or granular substances, the coloration of alumina oxide is the most obvious. In this case, the amount of sulfinylamide as a reaction reagent was preferably in the range of 0.01 to 0.1 g and the amount of naphthylethylenediamine hydrochloride was in the range of 0.01 to 0.1 g per 1 g of carrier. Moreover, the particle size of the carrier was most preferably about 200 mesosh. In addition to the above-mentioned alumina, silicon oxide may be used as the carrier for supporting the reaction reagents sulfinylamide and naphthylethylenediamine.

Magnesium oxide, calcium oxide, or a substance containing these as a main component is used. In addition, as a device for detecting nitrite ion concentration, a container with an opening for sample injection is used.
The tip of the opening is filled with absorbent cotton, and then filled with alumina carrying sulfanilamide and naphthylethylenediamine. It is best to use a transparent plastic tube or glass tube as the material for the container.

Example Examples are shown below.

Dissolve sulfanilamide 69 and naphthylethylenediamine hydrochloride 5g in 100ml of water, and mix this aqueous solution with 2o
Activated alumina sog of O mesh is mixed and water is evaporated and dried at about 60°C. In this way, activated alumina coated with sulfur-1-niamide and naphthylethylenediamine hydrochloride was filled into a glass tube with a length of 150 m and an inner diameter of 4 mm, filled with activated aluminum to a length of 80 m, and both ends were plugged with absorbent cotton. .

Figure 1 shows the nitrite ion detection column prepared in this way. 1 is a container made of a glass tube with both ends open, and 2 is a packed bed of activated alumina supporting sulfanilamide and naphthylethylenediamine hydrochloride. ,3
is absorbent cotton.

When this column was placed in a beaker containing water containing nitrite ions and sucked up from the bottom of the column to the top by capillary action, nitrite ions, sulf-7nylamide, and naphthylethylenediamine showed a color reaction in the packed bed. A red colored area as shown in Figure 2 was created. 4
indicates a colored part.

Note that the reaction of sulfinylamide and naphthylethylenediamine with nitrite ions is a diazotization reaction as described above.

Further, according to this example, the nitrite ion concentration in water is 1
For those with a value of 0/Q or more, the length of the red colored layer and the nitrite ion concentration showed a proportional relationship as shown in Figure 3, and could be detected with high accuracy.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the nitrite ion detection device used in the example of the present invention, FIG. 2 is a cross-sectional view of the colored state when water containing nitrite ions is tested using the same device, and FIG. The figure shows the relationship between the length of the colored layer and the nitrite ion concentration when water containing nitrite ions of known concentration was tested. DESCRIPTION OF SYMBOLS 1... Container, 2... Filled layer of activated alumina carrying sulfur 1 nylamide and naphthyl ethylene diamine, 3... Absorbent cotton, 4... Colored part. Name of agent: Patent attorney Toshio Nakao and 1 other person71
1 Figure 2 Figure 3 is 47 liters of nitric acid (su/l) = 211

Claims (2)

[Claims] (1) Bringing a test liquid into contact with a powdered or granular carrier layer supporting naphthylethylenediamine and sulfanilamide, and detecting nitrite ions in the test liquid based on the presence or absence of coloration of the carrier layer or its degree. A method for detecting nitrite ions, characterized by: (2) It consists of a container in which a partially transparent part is filled with a powdered or granular carrier carrying naphthylethylenediamine and sulfanilamide, and the container is characterized by having an opening for injecting the test liquid. Nitrite ion detection device.